About folkertsmit

When some people try to share a post on my site they get this error popup:
"The content is currently unavailable. The page you requested cannot be displayed right now. It may be temporarily unavailable, the link you clicked on may have expired, or you may not have permission to view this page."
What can this be? For me the sharing does work but some people reported the same problem.
Link: http://www.todays-specials.nl/news/food-drinks/de-kuyper-presenteert-internationale-bar-fight
At bottom click on "delen".

When i Facebook share a article on my site with your plugin i can see the image, but on facebook itself there is no image visible.
How can this be?
When i check the site on Facebook Debug site it does show image.
When i post directly on Facebook it also shows the image...
site url: http://www.todaysspe...remium-kc-toric
thx